how can i add zero padding to DFT

4 ビュー (過去 30 日間)
Moshe
Moshe 2016 年 5 月 1 日
回答済み: Star Strider 2016 年 5 月 1 日
Hi all, i write code that doing DFT for signal see code here:
f0=46.875;
W0=2*pi*f0;
Fs=1000;
T=1/Fs;
NFFT=512;
FFTperiod=NFFT*T;
t=(0:NFFT-1)*T;
str=['FFT period is ',num2str(FFTperiod), ' seconds'];
Freq=10*1/FFTperiod
strFreq =['Frequency is ', num2str(Freq), ' Hz'];
Freqbin =1/FFTperiod
strFreqbin =['FFT frequency bin is ',num2str(1/FFTperiod), ' Hz'];
strFreqNyquist =['FNyquist is ',num2str(1/FFTperiod*512), ' Hz'];
disp(str);
disp(strFreq);
disp(strFreqbin);
disp(strFreqNyquist);
x_t=sin(W0*t);
subplot(3,1,1)
plot(t,x_t);
title('time domain signal')
xlabel('Time')
ylabel('Amplitude')
Y=fft(x_t,NFFT)/NFFT;
f=Fs/2*linspace(0,1,NFFT/2);
subplot(3,1,2);
plot(f,abs(Y(1:NFFT/2)))
title('freq domain')
xlabel('Hz')
ylabel('Amplitude')
To this code i want to plot new graph with zero padding on the signal, that Change the length of the series to 4096.
can some one advise me how to do it?

回答 (2 件)

Azzi Abdelmalek
Azzi Abdelmalek 2016 年 5 月 1 日
x=[1 2 3]
y=[x zeros(1,10-numel(x))]

Star Strider
Star Strider 2016 年 5 月 1 日
Probably the best way is to use the nextpow2 function. See this documentation for fft for an illustration.

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